Purpose

Brompheniramine Maleate is an antihistamine having the chemical name, 2-Pyridinepropanamine,γ-(4-bromophenyl) -N, N-dimethyl-, (±)-,(Z)-2-butenedioate (1:1). Its structure is as follows:

C16H19BrN2•C4H4O4 M.W. 435.31

Phenylephrine Hydrochloride is an orally effective nasal decongestant having the chemical name, (–)-m-Hydroxy-α-[(methylamino)methyl]benzyl alcohol hydrochloride, an adrenergic which occurs as white or practically white, odorless crystals, having a bitter taste. It is freely soluble in water and in alcohol. Its structure is as follows:

C9H13NO2 • HCl M.W. 203.67

Dextromethorphan Hydrobromide is a salt of the methyl ether of the dextrorotatory isomer of levorphanol, a narcotic analgesic. Chemically, it is Morphinan, 3-methoxy-17-methyl-, (9α, 13α, 14α)-, hydrobromide, monohydrate. Its structure is as follows:

C18H25NO • HBr • H2O M.W. 370.32

TL-HIST DM Liquid - Clinical Pharmacology

Brompheniramine Maleate

Brompheniramine Maleate is classified as an alkylamine antihistamine. This class is among the most active histamine antagonists and is generally effective in relatively low milligram doses. Alkylamines cause a lesser degree of drowsiness and sedation than the phenothiazine antihistamines and hence may be more suitable for daytime use. It should be noted, however, that patients taking alkylamine antihistamines may experience some degree of drowsiness.

Dextromethorphan Hydrobromide

Dextromethorphan Hydrobromide is an antitussive agent which, unlike the isomeric levorphanol, has no analgesic or addictive properties. The drug acts centrally and elevates the threshold for coughing. It is about equal to codeine in depressing the cough reflex. In therapeutic dosage, Dextromethorphan Hydrobromide does not inhibit ciliary activity. Dextromethorphan Hydrobromide is rapidly absorbed from the gastrointestinal tract, metabolized by the liver and excreted primarily in the urine.

INDICATIONS

TL-HIST DM Liquid is indicated for the temporary relief of runny nose, sneezing, itching of the nose or throat, and itchy, watery eyes due to hay fever or other upper respiratory allergies or allergic rhinitis; for the symptomatic relief of respiratory conditions characterized by dry, non-productive cough and in the presence of tenacious mucus and/or mucus plugs in the respiratory tract; Nonnarcotic cough suppressant for the temporary control of cough due to minor throat and bronchial irritation associated with the common cold or inhaled irritants; calms the cough control center and relieves coughing.

Contraindications

Patients with hypersensitivity or idiosyncrasy to any of its ingredients. Do not use in newborn infants, premature infants, in nursing mothers, in patients with severe hypertension, severe coronary artery disease, ischemic heat disease, or in those receiving monoamine oxidase (MAO) inhibitors. Antihistamines are contraindicated in patients with narrow-angle glaucoma, urinary retention, peptic ulcer, and during an asthma attack. Antihistamines should not be used to treat lower respiratory tract conditions including asthma.

Warnings

Do not exceed recommended dosage. If nervousness, dizziness, or sleeplessness occur, discontinue use and consult a doctor.

If symptoms do not improve within 7 days or are accompanied by fever, consult a doctor. Do not take this product if you have heart disease, high blood pressure, thyroid disease, diabetes, or difficulty in urination due to enlargement of the prostate gland unless directed by a doctor.

A persistent cough may be a sign of a serious condition. If cough persists for more than 1 week, tends to recur, or is accompanied by fever, rash, or persistent headache, consult a doctor. Do not take this product for persistent or chronic cough such as occurs with smoking, asthma, or emphysema, or if cough is accompanied by excessive phlegm (mucus) unless directed by a doctor.

Use caution when giving to children or patients with chronic pulmonary disease, shortness of breath, difficulty in breathing, asthma, emphysema, high blood pressure, heart disease, diabetes, thyroid disease, or difficulty in urination due to enlargement of the prostate gland unless directed by a physician. Antihistamines may impair mental and physical abilities required for the performance of potentially hazardous tasks, such as driving a car or operating machinery, and may impair mental alertness in children. Antihistamines may cause hyperexcitability, especially in children. At doses higher than the recommended dose, nervousness, dizziness, or sleeplessness may occur.

Especially in infants and small children, antihistamines in overdosage may cause hallucinations, convulsions, and death. If nervousness, dizziness, or sleeplessness occurs, discontinue use and consult a doctor. Administration of Dextromethorphan Hydrobromide may be accompanied by histamine release and should be used with caution in atopic children.

If a hypertensive crisis occurs, these drugs should be discontinued immediately and therapy to lower blood pressure should be instituted immediately. Fever should be managed by means of external cooling.

Precautions

General

Before prescribing medication to suppress or modify cough, it is important to ascertain that the underlying cause of cough is identified, that modification of cough does not increase the risk of clinical or physiologic complications, and that appropriate therapy for the primary disease is provided. Because of its antihistamine component, TL-HIST DM Liquid should be used with caution in patients with a history of bronchial asthma, narrow-angle glaucoma, gastrointestinal obstruction, or urinary bladder-neck obstruction. Because of its sympathomimetic component, TL-HIST DM Liquid should be used with caution in patients with diabetes, hypertension, heart disease, or thyroid disease.

Information for Patients

Patients should be warned about engaging in activities requiring mental alertness and motor coordination, such as driving a car or operating machinery. Patients should be cautioned to get up slowly from a lying or sitting position and to lie down in nausea occurs. Alcohol or other sedative drugs may enhance the drowsiness caused by antihistamines.

Do not use if you are now taking a prescription monoamine oxidase inhibitor (MAOI) (certain drugs for depression, psychiatric, or emotional conditions, or Parkinson's disease), or for 2 weeks after stopping the MAOI drug. If you do not know if your prescription drug contains an MAOI, ask a doctor or pharmacist before taking this product.

CNS Depressants - concomitant use of antihistamines with alcohol, tricyclic antidepressants, barbiturates and other CNS depressants may have an additive effect.

Antihypertensives - the antihypertensive effects of guanethidine, methyldopa, mecamylamine, reserpine, and veratrum alkaloids may be reduced by sympathomimetics. Beta-adrenergic blocking agents may also interact with sympathomimetics.

Carcinogenesis, Mutagenesis, Impairment of Fertility

No data are available on the long-term potential of the components of this product for carcinogenesis, mutagenesis, or impairment of fertility in animals and humans.

Teratogenic Effects

Pregnancy Category C

There are no adequate and well-controlled studies in pregnant women. It is also not known whether TL-HIST DM Liquid can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. This product should be used during pregnancy only if the potential benefits to the mother justify the potential risks to the infant.

Nursing Mothers

Because of the higher risk of intolerance of antihistamines in small infants generally, and in newborns and prematures in particular, TL-HIST DM Liquid is contraindicated in nursing mothers.

Pediatric Use

Not recommended for use in patients under 2 years of age.

Geriatric Use

Confusion, dizziness, sedation, hypotension, hyperexcitability, and anticholinergic side effects, such as dryness of mouth and urinary retention (especially in males), may be more likely to occur in geriatric patients taking antihistamines. Geriatric patients taking sympathomimetics may be more likely to experience confusion, hallucinations, seizures and CNS depression. Geriatric patients may also be more sensitive to the effects, especially to the vasopressor effects of sympathomimetic amines.

Adverse Reactions

Slight to moderate drowsiness may occur. Other possible side effects common to antihistamines and decongestants in general include:

Overdosage

Signs and Symptoms

Since TL-HIST DM Liquid contains three pharmacologically different compounds, treatment of overdosage should be based upon the symptomatology of the patient as it relates to the individual ingredients. Therefore, it is difficult to predict the exact manifestation of symptoms in a given individual. A description of symptoms which are likely to appear after ingestion of an excess of the individual components follows.

In the event of overdosage, emergency treatment should be started immediately. Overdosage with Dextromethorphan may produce central excitement and mental confusion. Very high doses may produce respiratory depression. One case of toxic psychosis (hyperactivity, marked visual and auditory hallucinations) after ingestion of a single 300 mg dose of Dextromethorphan has been reported. Dextromethorphan Hydrobromide in toxic doses will cause drowsiness, ataxia, nystagmus, opisthotonos and convulsive seizures. Since there is no specific antidote for overdose, treatment is symptomatic and supportive with possible utilization of the following:

Induction of emesis (syrup of Ipecac recommended); however, precaution against aspiration is necessary, especially in infants and children. Gastric lavage (isotonic or 0.45% sodium chloride solution) if patient is unable to vomit within three hours of ingestion. Saline cathartics (milk of magnesia) are sometimes used.

Vasopressors to treat hypotension, however, epinephrine should not be used since it may further lower blood pressure. Oxygen and intravenous fluid. Precaution against the use of stimulants (analeptic agents) is recommended because they may cause seizures.

Short-acting barbiturates, diazepam, or paraldehyde, may be administered to control seizures. Hyperpyrexia, especially in children, may require treatment with tepid water sponge baths or a hypothermic blanket. Apnea is treated with ventilatory support.